The 7.1 version of HEAT2 is no longer available either as a trial or as a full product as the developer has moved on to newer versions of the tool. Furthermore, the edition that you mention was only designed for 32-bit systems, so it won't work on current 64-bit PCs.
In case you want to download the current free light edition of HEAT2, simply go to the developer's website, fill in the form providing your name and email, then go on from there.
